Cubane clusters with core

Cubane Clusters with fMFe3S 1 Core (M = Co2+. Zti2+. Cd2+)... 

The heteronuclear cluster [Mo3CoS4(H2O)10]4+ has been reported, where the Co is formally zerova-lent.168 The core structure (18) features two edge-linked cubane units with Co—S bridging the two clusters. 

Among the clusters derivatized by these methods, [ Mo(tacn) 3(PdCl)(n3-S)4]3+ (tacn = 1,4,7-triazacyclononane) is noteworthy, since this cluster can bind the substrate molecules such as alkene and CO at its tetrahedral Pd site generated by dissociation of the Cl anion. More interestingly, it has turned out that addition of ROH and RCOOH to various alkynes proceeds at this Pd site to give vinyl ethers and vinyl carboxylates catalytically.53 These reactions represent one of the yet rare examples that are catalyzed by well-defined cubane-type clusters with retention of their core structures. 

II. Incomplete Cubane-Type Clusters with Mo304. S Cores... 

V. Cubane-Type Mixed-Metal Clusters with Mo3MS4 Cores... 

In contrast to the situation a decade ago, many incomplete cubane-type clusters with Mo304 S cores have been prepared and the structures have been determined by X-ray structure analyses. The results obtained are summarized in Tables I—III. The formal oxidation state of molybdenum in the compounds cited here is in all cases IV. Unlike Mo(VI) and Mo(V) compounds, mononuclear oxo or dioxo compounds of the Mo(IV) state are relatively rare and all the incomplete cubane-type compounds cited here have no terminal oxo ligand. Three Mo atoms form an equilateral triangle, and three single bonds exist between each Mo. Except for the compounds 1, 8, and 31 (Table III), and excluding Mo—Mo bonds, each molybdenum is octahedrally coordinated. 

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